This invention is directed to the end of bringing to the individual student at his time and place of convenience the same classroom presentation that typically occupies the majority of the classroom time. And to accomplish this with equipment within the price reach of most students.
One means of fulfillment of this need has been via broadcast of live or video recorded Educational TV. Most students have access to the necessary equipment to receive such broadcasts. The draw-backs are that are limited number of courses are available at any one time, the geographic coverage is limited, scheduling as to time of day or day of week is not always convenient and if a student becomes confused on a concept he cannot resolve his problem by asking for clarification or by halting the presentation until he can clarify the concept by other references such as a text book.
Another means of fulfilling this need has been by use of movies. The per student cost for playback equipment is reasonable, however, the cost of preparation is high and also the cost of copies on a per use basis is high.
Another means has been use of audio tapes in conjunction with slides and workbooks. The cost of this equipment on a per student basis is reasonable. The problem with this approach is that the graphics are not in concurrence with the audio text, unless an excessive number of progressively completed graphics are provided. Otherwise the reference between the two presentations is tenuous.
Conversely, unambiguous reference between the oral and written texts accounts for the long and continued use of blackboards, and more recently the use of overhead projectors.
It is very desirable to develop the graphics in concurrence with the audio text. TV can do it and movies can do it, but neither can do it in an acceptable manner for reasons previously detailed.